[fix][sec] Upgrade commons-configuration2 to 2.15.0 to address CVE-2026-45205

[lhotari]

Motivation

Upgrade commons-configuration2 from 2.12.0 to 2.15.0 to address CVE-2026-45205, a medium-severity vulnerability affecting versions prior to 2.15.0.

The upgrade is a routine dependency bump within the 2.x line and is API-compatible.

Modifications

• Bump commons-configuration2 from 2.12.0 to 2.15.0 in gradle/libs.versions.toml.
• Update the bundled artifact name in distribution/server/src/assemble/LICENSE.bin.txt.

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Upgrades the commons-configuration2 dependency. API-compatible patch within the 2.x line.

Documentation

• doc-required
• doc-not-needed
• doc
• doc-complete